Automatic regulation in electric-lighting systems



F. C. LYNE ET AL AUTOMATIC REGULATION IN ELECTRIC LIGHTING SYSTEMS April 3, 1928. 1,664,519

Filed April 25. 1927 Patented Apr. 3, 1928.

, 1,664,519 PATENT OFFICE.

UNITED STATES FREDERICK CHARLES LYNE, OF WESTMINSTEE, LONDON, AND JAMES ETGHELLS, O1

ASTON, nmmnemm, ENGLAND, s'rna, LONDON, ENGLAND.

ASSIGNOBS TO VICKERS LIMITED, OF WESTMIN- A'U'I'OMATIC REGULATION IN ELECTRIC-LIGHTING SYSTEMS.

Application filed A ril The present invention relates to automatic regulation in electric lighting systems, such for example as train lighting systems, of the type in which the generator is required to supply a variable number of lamps and to charge a battery, its voltage being determined by a field regulator having shunt control.

According to this invention suppl of current from the generator to the amps is through a series resistance, which, when the main switch to the lamp load is closed, also carries the supply to the shunt coil of the regulator, which is so designed that a higher voltage than that necessary for the lamps but required to charge the battery is generated, the excess pressure being absorbed by the series resistance. When supply is from the battery the series resistance is short-circuited by a switch controlled by a solenoid in the generator circuit.

In order that the invention may be clearly understood and readily carried into effect it will now be described more fully with reference to the single figure of the accompanying drawing which represents diagrammatically one way of carrying it out.

Referring to t e drawing, a dynamo 1 is connected to supply a series of lamps 2 and to charge a battery 3. The regulator whereby the dynamo output and the voltage supplied to the lamps are controlled comprises a solenoid having a shunt winding 4 and a series winding 5, the latter being connected in'the charging circuit of the battery 3 in a manner already known. The solenoid operates a rolling contact 6 whereby.

value of a shunt field regulating resistance 7 is varied the arrangement being such that increase of current in either of the coils 4 or 5 augments the value of the resistance 7 connected in circuit.

In accordance with this invention a resistance 8 is connected in the dynamo circuit,

its terminals being short-circuited when the current is zero or is below a certain value 7 by a switch 9, the short-circuit being broken on the critical value being exceeded by operation of a solenoid 10 connected in series.

Alternatively the solenoid may be voltagecontrolled by connecting it across the namo terminals. As indicated, the resistance 8 is conveniently inserted between the positive terminal of the dynamo and the able for battery charging,

the

25, 1927, Serial No. 188,380, andin Great Britain larch 80, 1926.

main switch 11 of the lamp load 2. The sw1tch 11 is fitted with an auxiliary contact 12 whereby, when the switch is closed, the shunt coil 4 of the regulator is connected across the dynamo terminals through the reslstance 8. The shunt coil 4 is so proportioned that under these circumstances the voltage generated by the dynamo is suitthat is to say, is higher than that require by the lamp load, the excess of voltage being absorbed in the resistance 8. As indicated, however, the battery is so connected that its charging current does not pass through the resistance Sand therefore the higher voltage generated by the dynamo is applied for charging purposes. It will be seen that, as the lamp load increases by the switching in of a larger number of individual lamps, the augmented current will cause an increased voltage drop across the resistance 8 with the result that the regulating coil 4 will operate to cause the dynamo to generate a still higher voltage. Thus increase of the lamp load results in an increased rate of char e of the battery, whilethe voltage across tie lamp load is maintained constant. The shunt regulating coil 4 may also be connected across the dynamo terminals through a resistance 13, which may be of a higher value than the resistance 8, so that when the switch 11 is opened the coil 4 will still be operative to enable the dynamo to complete the charge to the battery. On discharge of the battery, when the dynamo either is not generating or its voltage is below a certain value, the switch 9 is allowed to close, thus short-circuiting the resistance 8 and the full batter voltage is therefore applied to the lamp loa In order to prevent discharge of the battery back through the dynamo when the latter is not running a reverse current switch of any suitable type will, in accordance with common practice, be inserted between the dynamo and the battery. 7 What we claim and desire to secure by Letters Patent of the United States is 1. An electric lighting system comprismg in combination a dynamo, a battery, connections whereby said battery may be supplied from said dynamo, a lam load, a fie regulating resistance for said ynamo, electroma etic means including a controlling coil w ereby the amount of said field regulating v resistance in series with the field winding of said dynamo may be varied, a

nections whereby series resistance, connections whereby said lamp load and said controlling coil may be supplied from said dynamo through said series resistance, a further resistance and connections whereby said further resistance and said controlling coil are connected in series with said dynamo.

2. An electric lighting system comprising in combination a dynamo, a battery, consaid battery may be supplied from said dynamo,.a lamp load, afield regulating resistance for said dynamo, electromagnetic means including a controlling coil whereby the amount of said field regulating resistance in series with the field winding of said dynamo may bevaried, a. -ser1esres1stance, connections whereby saidlamp load and said controlling coil may be supplied from said dynamo through said series resistance, a further resistance, connections whereby said further resistance and said controlling coil are connected in series with said dynamo, and means for placing said series resistance and said further reresistance in series with the field winding of said dynamo may be varied, a series resistance, connections whereby said lamp load and said controlling coil may be supplied from said d namo through said series resistance, a, urther resistance and connections whereby said further resistance-i and said controlling coil are connected in series with said dynamo,'a short-circuiting switch for said series. resistance and said further *resistance, and means whereby said'shortcircuiting switch is opened when the supply from the said dynamo exceeds a given value.

FREDERICK CHARLES LYNE. JAMES E'roHnLLs. I 

